焊接氢致裂纹的模拟与预测

Mathematical Modeling and Prediction of Welding Hydrogen-Induced Cradck

焊接氢致裂纹是金属氢损伤在焊接中的一种表征。它的产生与焊接接头中的组织、应力和局部氢浓度密切相关 ,迄今尚没有可行的技术 ,测定焊接氢致裂纹开裂时启裂处的局部氢浓度 ,即无法确定焊接氢致裂纹开裂的临界氢浓度 ,因而无法进行焊接氢致裂纹的模拟预测。通过用数值模拟技术与可以定量评定焊接氢致裂纹的插销试验法相结合 ,确定了氢致裂纹启裂时的临界局部氢浓度 ,建立焊接氢致裂纹的定量判据 ,实现了焊接氢致裂纹的模拟预测。试验验证结果证明该项技术是可行的。

The atom of hydrogen is the lightest and smallest one among elements,it is movable easily.within crystal lattice of metal even at room temperature.Welding hydrogen induced crack(HIC) is a kind of hydrogen damage of metal during welding of high strength low alloy steel.Its occurrence is related to micro structure,residual stress and local hydrogen concentration in weldment.Up to now,unfortunately,there is no way to check the critical local hydrogen concentration in the vicinity of the initiation of HIC.In this paper the mathematical modeling method combined with quantitative implant cold cracking testing is developed to determine the local critical hydrogen concentration based on the local critical stress in the vicinity of the initiation area of HIC,therefore the criterion for HIC is established.According to the criterion the mathematical modeling and prediction of welding HIC are realized.The experiment shows that the modeling and prediction of welding HIC are feasible.